This invention relates to the use in electronic equipment and the like of rechargeable backup batteries for enabling continued operation of the equipment during power failure of the main equipment battery or source normally designed to power the equipment; being more particularly concerned with minimizing unnecessary depletion of such a main equipment battery to maintain the charge of the backup battery.
More specifically, the invention addresses the particular problems and potential resources arising wherein, for example, radio communication electronic transponders/transceivers are operated from a vehicle engine battery, as in remotely scattered construction vehicles and the like, to communicate to a remote central monitoring station, GPS location information received at the vehicle, and also locally sensed operating conditions of the vehicle, via communication links, including via the Internet web page or otherwise, to such a remote central station.
In co-pending application Ser. No. 09/016, 604, filed Oct. 12, 1999, an improved monitoring system of this nature is described, also referencing other such systems, wherein a construction equipment fleet manager is supplied at the central station with information and selective displays containing all the basic information, suitably processed, needed remotely to track, monitor and maintain the operation of the fleet and to improve efficiency of utilization of the equipment.
The transponder/transceiver electronic radio communications links described in said copending application, including those offered by Orbcomm USAxe2x80x94Orbital Science Corp., and others, are provided with backup batteries, generally chargeable from the vehicle equipment main batteries, which, in turn, are chargeable from the vehicular engine alternators when the engines are running.
While the art is replete with backup battery and charging circuit configurations for other uses, such as, for example, as disclosed in U.S. Pat. No. 5,387,858, the techniques therein used are not, however, specifically adapted for the particular vehicular engine monitoring requirements of the present invention.
As earlier indicated, the invention is concerned with effecting this backup battery charging in an efficient manner without unnecessarily depleting energy from the vehicle equipment main battery, as by consuming current when the backup battery is already fully charged.
As a power source, the vehicle equipment main battery has the following operating characteristics. While the equipment is operating, the supply of power is plentiful and the main vehicle battery may be recharged by the mechanical operation of the engine, as via the alternator. During periods of time when the vehicle engine is not operating, however, the inefficiency of the electronic equipment backup battery may be a significant factor in running down the vehicle equipment main battery in an unacceptably short time. When, furthermore, the vehicle equipment battery is disconnected, as for servicing or transport of the equipment, it is essential that the electronic equipment backup battery be maintained sufficiently fully charged to support continued operation for a sufficient period of time, for purposes such as communicating knowledge of such disconnection to the central station or periodically reporting its position to the central station in case of unauthorized transport.
The invention specifically addresses these particular circumstances by monitoring whether the equipment is running, and if so, exploiting the plentifulness of power to supply power to the electronic equipment and to charge its backup battery as much as possible.
If, however, the vehicle engine is not running, the invention then enables detecting or estimating by one of various means, the charge state of the backup battery; and when the backup battery is nearly fully charged, controlling power to the electronic equipment, allowing it to run off its backup battery for a period of time consistent with efficient recharging but not so long that the backup battery becomes too depleted to meet its intended requirements. Power is then restored to the electronic equipment for a period of time, allowing it to charge its backup battery to the point at which it is again nearly fully charged.
Various means for effecting the detection or estimation of the charge state of the electronic equipment backup battery may be employed, the selected means preferably adapted to providing, the lower-cost solution for a given amount of savings available by mitigating the inefficiency of the electronic equipment, a given vehicle equipment battery capacity, a given backup battery capacity, and a given operational or fail survival time requirement on the electronic equipment.
Specifically, in accordance with the technique of the invention, the monitoring of the electronic equipment backup battery open circuit voltage and charging current, in consort with consideration of the total current or charge drawn from the backup battery since its last charge, can enable such efficient use of the main vehicle battery and the electronic equipment backup battery. This result, moreover, can be attained irrespective of whether the equipment engine that charges the vehicle main battery, is or is not running, and the backup battery voltage is or is not under load. The consideration of these parameters, indeed, enables measuring the state of the electronic equipment backup battery charge when the vehicle engine is not operating; and when it is noted that there has been a predetermined discharge from complete charge, turning the charger circuit on in order rapidly to top off or bring the backup battery up to full charge, and thereupon turning the battery charger off. This enables efficient charging that minimizes energy wasting.
The primary object of the present invention, accordingly, is to provide a new and improved method of and apparatus for regulating power consumption by vehicle-carried electronic equipment such as radio transponder/transceiver communication equipment or the like containing integral re-chargeable backup batteries, wherein the electronic equipment operates from vehicle engine-charged batteries and the like, requiring backup battery power and re-charging when the engine shuts off, and, with the invention being particularly suited for use in remote equipment monitoring systems, though being of more general utility, as well.
Other and further objects will be pointed out hereinafter.
In summary, however, from one of its important aspects, the invention embraces, in a vehicular engine equipment system provided with an engine-chargeable main battery and provided also with engine operational information (and, if desired, positional information) communicating electronic radio transponder/transceiver communication equipment having backup batteries, a method of enabling the efficient charging of such backup batteries from the main battery while regulating the power consumption by the communication equipment, that comprises, charging the main battery from and at the engine during the operating of the engine; fully charging the back-up battery from the main battery and thereupon terminating such charging; monitoring the charge state of the backup battery during periods of non-operating of the engine and of demands upon the backup battery by the communication equipment; and, upon the monitored reaching of a predetermined level of discharge of the backup battery, further charging of the same from the main battery back to full charge and thereupon terminating such further charging; and repeating said monitoring and further charging and terminating as needed during the continued non-operating of the engine and the continued operational power demands of the communication equipment.
Preferred and best mode implementations and designs are later detailed.